Wavelet and recurrence analysis for lean blowout detection: An application to a trapped vortex combustor in thermoacoustic instability

In flames, extinctions and subsequent re-ignitions occur continuously, with such small lifetime that they are difficult to perceive. Here, the light emitted by a vortex in reactive conditions is sampled in time and projected on a wavelet base. The result of the analysis is a statistical description of these shutdown and re-ignition phenomena in terms of the event duration, occurrence, amplitude, and shape. The proposed data analysis technique is applied for the first time in the field of combustion, but has had a widespread application in nonreactive fluid dynamics and aeroacoustics.